Dr. Cziczo explains the difference between millions of years of natural warming cycles and the more recent anthropogenic warming caused by the production of more CO2. He discusses the implications of atmospheric CO2 buildup and the limitations of geoengineering and sequestration as solutions to this problem. Daniel Cziczo, Professor and Head, Earth, Atmospheric and Planetary Science, Purdue University. Recorded at Purdue University. 00:34:24